As social media has become used more extensively, classification of users of social media by “preferences and interests” for use in marketing has become more widely known. For example, these classifications are used to identify products and services the user is likely to purchase, and segmentation of large-scale user sets (classification according to similar interests). There have been attempts to identify sets on the assumption that users of a similar age and political orientation post similar content on social media. For example, efforts have been made to estimate the age and political orientation of users using content similarity (Non-patent Literature 1 and Non-patent Literature 2), and these efforts have had some success. Estimating sets of users sharing common preferences and interests using a similar technique is believed to be theoretically possible.